Vapor generator



2 Sheets-Sheet 1 Filed Feb. 7, 1957 FIG. 1

INVENTOR. Norman W. Young AT TORNEY April 11, 1961 N. w. YOUNG VAPORGENERATOR 2 Sheets-Shet 2 Filed Feb. 7, 1957 INVENTOR.

Norman W. Young ATTORNEY VAPOR GENERATOR Norman W. Young, HuntingtonStation, N.Y., assignor to The Babcock & Wilcox Company, New York, N.Y.,a corporation of New Jersey Filed Feb. 7, 1957, Ser. No. 638,704

Claims. (Cl. 122510) The present invention relates in general to theconstruction of vapor generators. More particularly, the inventionconcerns the provision of a vapor generator in which the pressure partsare entirely bottom supported and a predominant proportion of thepressure-part loading is carried by a support arrangement includingfluid supply tubes of the circulation system.

Boiler and furnace wall tubes of a vapor generator are usually supportedby the drums or headers to which they are connected. Some vaporgenerators are bottom supported from the lower drums and headers whileothers are suspended from the upper drums. The large quantity ofvertical supporting steel required for a top supported vapor generatormakes such a support arrangement quite expensive. Further, a topsupported vapor generator requires relatively high headroom, and makesaccess difficult to some of the parts of the setting. Heretofore, inbottom supported vapor generating units, it has been necessary to limitthe difference in elevation between points of vertical support of thelower drums and furnace walls to avoid excessive stresses on these andassociated parts occasioned by relative vertical expansion movements.This limitation imposes a definite restriction in the height of thefurnace chamber, and, consequently, a definite limitation in the steamgenerating capacities of such units.

In accordance with the present invention, the various boiler pressureparts are bottom supported at approximately the same elevation, with apredominant proportion of the weight of the drums and tubes extendingtherebetween being carried by a support arrangement which includesupright tubes extending downwardly from the lower drum and supplyingfluid to at least some of the furnace wall tubes. The supportarrangement of the invention permits the setting of the furnace heightwithout limitation imposed by the difference in elevation between thelower drum and the point of support of the furnace wall tubes, providescomplete freedom for necessary expansion and minimizes relative verticalexpansion movements between the furnace wall tubes and the boiler drumsand tubes. Moreover, the supporting members of the invention reflect asimplification in the support arrangement of bottom supported vaporgenerating units that eliminates superfluous steel and provides easyaccess to all parts of the setting for inspection and repair. Theinvention is particularly advantageous with stoker firing since there isno need for the slip type sealing joints heretofore required in the wallsupport arrangement of units so fired.

The various features of novelty which characterize the invention arepointed out with particularly in the claims annexed to and forming apart of this specification. For a better understanding of the invention,its operating advantages and specific objects attained by its use,reference should be had to the accompanying drawings and descriptivematter in' which certain specific embodiments of the invention areillustrated and described.

2,979,041 Patented i, test Fig. 1 is a somewhat diagrammatic sectionalelevation of a vapor generating unit embodying the invention;

Fig. 2 is a sectional rear elevation of the lower half of theillustrated embodiment taken along the line 2-2 of Fig. 1; and

Fig. 3 is a fragmentary sectional side elevation showing a modification.

Figs. 1 and 2 illustrate an embodiment of my invention in the form of avapor generator comprising a twodrum water-tube boiler deriving heatfrom a Stoker-fired furnace. The vapor generator enclosure or setting isof substantially rectangular cross-section and comprises a verticallyextending furnace chamber 10 defined by fluid cooled walls including afront wall 12, a lower rear wall 14, side walls 16, and an upper wall orroof 18. The rear portion of the setting includes a boiler space 20laterally adjoining the upper portion of the furnace chamber 1t) anddefined by lateral extensions of the side Walls 16 and an upper rearwall 22 rearwardly offset from the lower rear wall 14. The upper rearwall 22. is formed with an outlet 24 for discharge of gases from thesetting.

A two-drum natural circulation boiler 26 is positioned at the rear ofthe setting and arranged for single-pass gas flow therethrough in agenerally horizontal direction. The boiler pressure parts includehorizontally disposed upper and lower drums 28 and 30 having theirlongitudinal axes lying in substantially the same vertical plane; andupright boiler tubes arranged in horizontally spaced banks 32, 34 andconnected at their upper and lower ends to the upper and lower drums 28and 30, respectively.

The lower rear portion of the boiler space 20 is formed by a series ofhoppers 33 extending between the side walls 16, with each hopperhavingits inclined rear and front walls extending convergently from thebottom of the rear wall 22 and from the drum 30, respectively.

The furnace chamber 10 is fired by a conventional chain grate stokerincluding a traveling chain grate 35 located at the bottom of thefurnace chamber 10 and having its top run arranged to move toward therear wall 14. The grate 35 is arranged to receive solid fuel, such ascrushed coal, from suitable fuel delivery appara tus including a hopper36 disposed supeijacent the front end of the grate 34. Air forcombustion is delivered in suitable known manner to the space betweenthe upper and lower runs of the grate. An ash discharge hopper or pit 38is provided subjacent the rear end of the grate 35. Other fuels such asoil or gas may be burned, in which case the furnace may be easilyadapted in known manner for such firing.

The boiler pressure parts also include fluid cooled tubes for all thefurnace walls, the front wall 12 and roof 18 having a row of tubes 40connected at their lower ends to a header 42 and at their upper ends tothe drum 28, with fluid supply being provided by tubes 44 extendingbetween the lower drum 32' and the header 42; each side wall 17 having arow of tubes 46 connected at their opposite ends to headers 48 and 50,with fluid supply being provided by tubes 52 extending between the lowerdrum 30 and the header 48 and fluid discharge being provided by tubes 54extending between the header 50 and the upper drum 2S; and the lowerrear wall having a row of tubes 56 connected at their lower ends to aheader 58 and at their upper ends to the upper drum 28, with the upperportions of these tubes being arranged to form a screen ahead of theboiler tube bank 32 and with fluid supply being provided by uprighttubes 60 extending between the lower drum 30 and the header 58.

In accordance with the invention, the pressure parts of the boiler andits associated furnace are specially arranged for bottom support atsubstantially the same elevation to minimize relative expansionmovements between different pressure parts. The points of fixed supportindicated in Figs. 1 and 2 are at the lower rear wall header 58 and atthe side wall headers 48, so the pressure parts are free to expandupward and laterally. The predominant proportion of the weight of thedrums 28, 30 and tube banks 32, 34, preferably substantially all of theweight of these parts, is taken by a support arrangement including theupright supply tubes 60 disposed at spaced position-s along the lengthof the drum 30, the lower header 58, and upright steel columns 62 atspaced positions along the length of the header 58 having saddles 64 attheir upper ends placed under the header 58. Thus the tubes 60 functionassupply tubes in the fluid circulation system and as, in efiect, partof the support columns for the boiler pressure parts. These tubes areprovided in sufiicient number and are of sufficient diameter andthickness to resist bending moment stresses in carrying the weight ofthe boiler tubes and drums and to withstand the compression forcestransmitted to them.

The rear end of the stoker is enclosed by a refractory wall 66 extendingtransversely of the furnace chamber between the side walls.

The provisions for supporting the furnace wall tubes and associatedheaders, as well as the remainder of the weight of the drums and tubesextending therebetween not supported as described above, comprises a airof support castings or columns 68 placed under and expansibly secured inknown manner to each side wall header 48, with a point of fixed supportbeing at substantially the same elevation as the corresponding point forthe boiler drums and tube banks. The header 42 is connected to andsupported from the ends of the headers 48 by short drain tubes 79.

The fluid in the portion of the circulation circuit including the tubes69 is water at or close to the satura tion temperature corresponding tothe drum pressure, while the fluid in the portions of the circulationcircuits including the furnace wall tubes is a mixture of steam andwater also at the saturation temperature corresponding to the drumpressure. With the drums and tube banks and furnace wall tubes supportedas described there is little or no relative expansion between thefurnace wall tubes and the boiler drums and tubes since the points offixed support of all pressure parts are set at substantially the sameelevation and since the inside surfaces of all pressure parts of thesetting are at or close to the temperature corresponding to the drumpressure. This arrangement allows establishment of the furnace heightwithout regard to the difference in elevation between the lower drum andthe point of support of the furnace wall tubes. Further, simplicity andcompaotness are enhanced with the supporting members so arranged..Headroom requirements are relatively low because overhead beams orother building tie-in steelwork are eliminated. There are no steelsupporting members to interfere with operations adjacent to the vaporgenerating unit and access to any part of the unit is facilitated.

In the operation of the vapor generating unit described, the supplies ofair and fuel are fed to the furnace in controlled quantities, andcombustion of the fuel takes place at a relatively rapid rate. All ofthe heating gases generated flow upwardly through the furnace chamber,then substantially horizontally over the screen tubes and the tube banks32, 34 to the gas outlet 24. The last four or five rows, with respect togas flow, of the tube bank 34 serve as downcomer or fluid supply tubesfor the remaining portion of the bank and'for tube bank 32, and thesupply tubes 44, 52, 6t) deliver adequate supplies of water to thefurnace water walls.

In the embodiment illustrated in Fig. 3, the boiler pressure partsupporting members include a group of upright fluid supply and supporttubes 72 arranged at each end of the drum 30, with the tubes of eachgroup having their drum connection ends circu-mferentially spaced, theiropposite ends connected to rearward extensions of the lower side wallheaders, and their centerlines lying in substantially a single verticalplane extending generally normal to the vertical plane including thelongitudinal axis of the drum 30; and steel columns 68 at spacedpositions along-the length of each side wall header 48 having saddles attheir upper ends placed under the respective headers. 'le this supportarrangement is adapted to carry the entire weight of the drums, tubebanks, and furnace walls, part or substantially all of the support ofthedrums and tube banks may be provided by the supporting members for thecorresponding parts in the main embodiment of Figs. 1 and2, that is, bythecolumns 62, header 58 and tubes 60. Like the embodiment of Figs. 1and 2, the points of fixed support of all pressure parts are set atsubstantially the same elevation and there is little or no relativeexpansion between diiferent parts.

While in accordance with the provisions of the statutes I haveillustrated and described herein the best form of the invention nowknown to me, those skilled in the art will understand that changes maybe made in the form of the apparatus disclosed without departing fromthe spirit of the invention covered by my claims, and that certainfeatures of my invention may sometimes be used to advantage without acorresponding use of other features.

What is claimed is:

1. A bottom supported vapor generating unit having a natural circulationfluid circulation system and comprising walls forming a settingcontaining pressure parts including horizontally disposed upper andlower drums, and a bank of upwardly extending tubes connected at theiropposite ends to said drums; some of said walls including fluid cooledtubes and forming sides of a furnace chamber laterally adjacent andopening to said tube bank; column support means constructed and arrangedto provide column strength sufllcient to support at least a predominantproportion of the weight of said drums and tube bank; said columnsupport means constituting horizontally extending header means disposedbelow said lower drum, a plurality of laterally spaced upright tubesdisposed along the length of said lower drum and connected at theiropposite ends to the lower drum and to said header means, and means forbottom supporting said header means; said upright tubes being ofsufficient diameter and thickness to resist bending moment stresses incarrying said drums and tube bank and to withstand the compressionforces transmitted to them; said upright tubes, said header means, andsaid bottom support means for said header means constituting the normalsupport means for the predominant proportion of the weight of said drumsand tube bank; means connecting said fluid cooled tubes and said headermeans into said fluid circulation system; and means for bottomsupporting said fluid cooled wall tubes at approximately the sameelevation as the means for bottom supporting said header means tothereby minimize relative vertical expansion movements between saidfluid cooled wall tubes and said drums and tube bank.

2. A bottom supported vapor generating unit having a' naturalcirculation fluid circulation system and comprising walls forming asetting containing pressure parts including horizontally disposed upperand lower drums having their longitudinal axes in substantially the samevertical plane, and a bank of vertically extending tubes connected attheir opposite ends to said drums; some of said walls including fluidcooled tubes and forming sides of a furnace chamber laterally adjacentand opening to said tube bank; column support means constructed andarranged to provide column strength suflicient to support at least apredominant proportion of the weight of said drums and tube bank; saidcolumn support means constituting horizontally extending header meansdisposed below said lower drum, a plurality of laterally spaced uprighttubes disposed along the length of said lower drum and connected attheir opposite ends to the lower drum and to said header means, andmeans for bottom supporting said header means; said upright tubes beingof sufiicient diameter and thickness to resist bending moment stressesin carrying said drums and tube bank and to withstand the compressionforces transmitted to them; said upright tubes, said header means, andsaid bottom support means for said header means constituting the normalsupport means for the predominant proportion of the weight of said drumsand tube bank; means connecting said fluid cooled tubes and said headermeans into said fluid circulation system; and means for bottomsupporting said fluid cooled wall tubes at approximately the sameelevation as the means for bottom supporting said header means tothereby minimize relative vertical expansion movements between saidfluid cooled Wall tubes and said drums and tube bank.

3. A bottom supported vapor generating unit having a natural circulationfluid circulation system and comprising walls forming a settingcontaining pressure parts including horizontally disposed upper andlower drums having their longitudinal axes in substantially the samevertical plane, and a bank of vertically extending tubes connected attheir opposite ends to said drums; some of said walls including fluidcooled tubes and forming sides of a furnace chamber laterally adjacentand opening to said tube bank; column support means constructed andarranged to provide column strength suflicient to support at least apredominant proportion of the weight of said drums and tube bank; saidcolumn support means constituting a horizontally extending headerdisposed below said lower drum, a plurality of laterally spaced uprighttubes disposed along the length of said lower drum and connected attheir opposite ends to the lower drum and to said header, and means forbottom supporting said header; said upright tubes being of suflicientdiameter and thickness to resist bending moment stresses in carryingsaid drums and tube bank and to withstand the compression forcestransmitted to them; said upright tubes, said header, andsaid bottomsupport means for said header constituting the normal support means forthe predominant proportion of the weight of said drums and tube bank;means connecting said fluid cooled tubes and said header into said fluidcirculation system; and means for bottom supporting said fluid cooledwall tubes at approximately the same elevation as the means for bottomsupporting said header to thereby minimize relative vertical expansionmovements between said fluid cooled wall tubes and said drums and tubebank.

right tubes disposed along the length of said lower drum and connectedat their opposite ends to the lower drum and to said header, and meansfor bottom supporting said header including upright columns each havinga cradle at the top end thereof carrying said header; said upright tubesbeing of suflicient diameter and thickness to resist bending momentstresses in carrying said drums and tube bank and to withstand thecompression forces transmitted to them; said upright tubes, said header,and said bottom support means for said header constituting the normalsupport means for the predominant proportion of the Weight of said drumsand tube bank; means connecting said fluid cooled tubes and said headerinto said fluid circulation system; and means for bottom supporting saidfluid cooled wall tubes at approximately the same elevation as the meansfor bottom supporting said header to thereby minimize relative verticalexpansion movements between said fluid cooled wall tubes and said drumsand tube bank.

5. A bottom supported vapor generating unit having a natural circulationfluid circulation system and comprising Walls forming a settingcontaining pressure parts including horizontally disposed upper andlower drums having their longitudinal axes in substantially the samevertical plane, and a bank of vertically extending tubes connected attheir opposite ends to said drums; some of said walls including fluidcooled tuba and forming the side walls of a furnace chamber laterallyadjacent and opening to said tube bank, with the fluid cooled tubes ofsaid side walls having their lower ends connected to horizontallyextending headers disposed at the same elevation and arranged with theirlongitudinal axes substantially normal to the longitudinal axis of saidlower drum and with each header having a portion thereof situated belowsaid lower drum; column support means constructed and arranged toprovide column strength suflicient to support the entire weight of saiddrums and tube banks and fluid cooled tubes; said column support meansconstituting said headers, groups of upright tubes disposed adjacentboth ends of said lower drum and connected at their opposite ends to thelower drum and to said side wall headers, with the tubes of each grouphaving their centerlines lying in substantially a single 'vertical planeextending generally normal to the longitudinal axis of the lower drum,and means for bottom supporting said side wall headers at the sameelevation including upright columns at spaced positions along the lengththereof; said upright tubes being of sutficient diameter and thicknessto resist bending moment stresses in carrying said drums and tube bankand to withstand 4. A bottom supported vapor generating unit having anatural circulation fluid circulation system and comprising wallsforming a setting containing pressure parts including horizontallydisposed upper and lower drums having their longitudinal axes insubstantially the same vertical plane, and a bank of verticallyextending tubes connected at their opposite ends to said drums; some ofsaid walls including fluidjcooled tubesand forming sides of a furnacechamber laterally adjacent and opening to said tube bank; column supportmeans constructed and the compression forces transmitted to them; saidupright tubes, said header, and said means for bottom supporting saidheader constituting the normal support means for the entire weight ofsaid drums and tube bank and fluid cooled tubes; and means connectingsaid fluid cooled tubes and said header into said fluid circulationsystem.

References Cited in the file of this patent UNITED STATES PATENTS 1OTHER REFERENCES Steam its Generation and Used The Babcock 8;

Wilcox C0.,.1955, Page 2916.

